1. Field of the Invention
The present disclosure relates to a method and apparatus of establishing a sleep mode operation, and more particularly, to a method and apparatus of establishing a sleep mode operation in a multi-carrier system.
2. Description of the Related Art
With the development of the communication technology, services provided by a mobile communication system are being gradually developed into packet data transmission and/or reception services, multimedia broadcasting services, and the like, as well as voice communication services.
In the third generation services, such as WCDMA currently being serviced, high capacity data as well as voice can be transmitted and received at a high transmission rate, and furthermore, the standardization work is actively carried out, such as long-term evolution network (LTE), IEEE 802.16m, and the like, in order to make an evolved network having a wider bandwidth, considering a rapid increase of data traffic in the future.
In particular, IEEE 802.16m, for which its standardization work is carried out, has set a goal to develop a standard specification satisfying the requirement of an IMT-Advanced system while maintaining compatibility with existing 802.16-based terminals and base station equipment. In the IMT-Advanced system, above all, more than 40 MHz of broadband communication service support is required, and in IEEE 802.16m, broadband communication support is also essential to satisfy the requirement of the IMT-Advanced system. However, it is in fact difficult to define a standard for all bandwidths, and as a result, a communication system using a multi-carrier approach that supports broadband using a plurality of carriers is under discussion. In the multi-carrier system, discussed under IEEE 802.16m, it is possible to transmit and/or receive data between a terminal and a base station by accessing to each other through at least two and more frequency assignments (FAs) at the same time, and therefore, it has an advantage that high-capacity, high-speed data transmission and reception is possible compared to the existing single-carrier approaches. Also, it has a feature that communication is possible using a broader bandwidth from the standpoint of a mobile station (MS) depending on circumstances, and more users can be accommodated from the standpoint of a base station (BS).
On the other hand, since the mobility of terminals is considered in a wireless mobile communication system, the problem of power consumption in terminals may be a considerably important element compared to other systems. The sleep mode operation between a terminal and a base station has been proposed as one of such methods for minimizing power consumption in the terminal.
In the sleep mode operation in a single-carrier system, a terminal requests to enter into a sleep mode if there exists no more traffic to be transmitted and/or received to and/or from a base station while performing communication with the base station in an active mode, and receives a response to that request from the base station to change the state thereof to a sleep mode.
The terminal that has entered into a sleep state receives a message indicating whether there exists a traffic transferred from the base station during a sleep listening window, and determines that there exists no data traffic transmitted to a downlink, and increases the current sleep cycle if negative indication indicating that there exists no traffic is received.
Furthermore, if positive indication is received from the base station during the listening window, then the terminal determines that there exists data traffic transferred to a downlink, and initializes the current sleep cycle.
However, since multiple carriers are used in a multi-carrier system, the existing single-carrier system sleep mode operation cannot be applied thereto as it is, and thus there is a need for presenting sleep mode parameters for supporting more effective sleep mode operations in a multi-carrier environment, and a detailed sleep mode operation method in a multi-carrier system using the same.